Stencil for sand-blast etching.



,0. G. BECHER.-

STENCIL FOR SAND BLAST ETCHING.

APPLicATioN FILED Aua.1 8. 1916.

1,265,989. l Patented May14,1918.

orme. BECKER, or emana, NEBRASKA.

s'rENcn. non Asairnnnlaszr ETCHING.'

' Specication of Letters Patent. .VPatented May 14, 1918. l

i 'application med August is, 191s. serial No. 115,734.

To ll lwhom it may concern.'

Be it known that I, OTro G. BECKER, a citizen of the United States, and a resident of Omaha, in the county of Douglas and State of Nebraska, have invented cerfollowing is a specification.

My invention relates tothe art of etchingY glass, metals, porcelain, vitrolite, marble, and the like, by the use of a sand-blast operating through the openings of a stencil which determines the-form, pattern or desi to be getched. It is the object of my invention to provide eiiicient and inexpensive stencils for use in sucl etching processes, and particularly to provide an inexpensive composition of matter such that a relatively thin layer thereof will resist the action of a sand-blast sufficiently to enable a proper abrasion vor etching of the surface not protected by the composition forming the stencil. 4

In the accompanying drawings Figure 1 is a perspective view 'illustrating a partially completed stencil embodying my invention, and Fig. 2 vis a detail sectional view of the same.

In ca ing' out my invention I provide a composltion of which the approximate proportions and mode of preparation are as follows:

Ten (10).pounds of dried white glue is covered with water in a suitable receptacle such as woodenpail or vat,.and the receptacle then covered and `put in a cool place for about 48 hours or until the glue is thor- `oughly softened;` Equal parts of the softened glue land of water are then 'placed' 40 in a vessel of suitable capacity, say 10 to `15 quarts, and `said vessel laced in a largervessel which is partially ed with'water. To the mixture of glue and water there .is added l to 111 ounces of boiled linseed 4 5 oil, and about-l ounce of powdered carbonate of 'magnesia The ingredients are then heated by the water inA the outer veel to boilin temperature for 15 to 20 minutes, and w e heated4 arestirred `and thoroughly mixed to a unl- 'formconsistency Enough glycerin 4is then p added to 'make the composition while hot4 have the`consistency of thin syrup. Thev amount of -gl cerin required will aver' about l ounce ut will vary according to t e quality of the glue and the season (summerv .coated sides thereof will not .come into conthe ingredients or winter) in which the preparation is used, more of the 'glycerinbeing used in warmweather.

For use in making stencils, a coating of6'0 l. the described mixture'or composition is aptain new land useful Improvements ln-Stenn- Acils for Sand-Blast Etching, ofwhich the? plied'to one side of sheetsof paper of suit. able size, the operation being preferably about as follows: A ood quality ofdraw.

ing paper is chosen, aving a rough side 'and a smooth side for drawing. A board, of suitable size for receiving the sheets of paper to be coated, is provided wiith a smooth surfacing as by placing thereon a plate of glass or smooth sheet-metal such *l as copper, the board preferably havingat opposite `sides two projecting strips adapted to engage the edges of the paper sheet to conne the same between them. As each sheet of the paper is coated, it is first mois- A tened bysponging with a damp cloth or the likeA on the rough side, thenlaid with the smooth side against the surface of the board between the -retaining side-strips, and the sheets then pressed out smboth and flat upon the surface. The compositionl while still heated is then spread quickly over the surface of the paper, as evenly as possible, so

. as to form a coating having a thickness ofv about'gg of an inch. The coating may be 85 Vsmoothed and made more even and uniform in thickness by passing over it a roller or a strip of glass which has been warmed by immersion in heated Water. The coated sheets whenfremoved from the board are hung up in a cool room where the temperature will not exceed v50 degrees F., the sheets' being' arranged on round sticks or the'like so as not to be sharply bent and so that the tact with any object untilthey are desiredA for use. It is advisable not to prepare at one time more of the sheets than can be used in about a week, as after such tlme the coating is liable to become hard and use` less.

lIn the use of the coated aper, prepared as above described, the sur ace of the arti,

cle Vto be etched orengraved is first thoroughly cleaned, andthe coated side of the paper issthen applied to the surface and` the paper. rubbed or rolled to bring the composition coating into perfect contact with the surface, care being taken that no airbubbles or foreign particles are allowed to remainbet'ween the coated paper and the surface to which is applied. When in ioo of sai proper condition thc-prepared paper will adhere quite firmly to anyl smooth surface as of glass, metal, marble, porcelain, or the like, such as it may be desired 'to etch or engrave bythe use of a sand-blast, but the paper and compositionv coating may be detaehedjfrom thel Surface by first loosening one edge thereof and then peeling the same off from said edge.

Afterthecoated paper has been applied to the surface as abovedescribed, the desired design is drawn or stenciled on the surface of the paper, and thereafter said .surface is washed over with a thin solution of glue to form a thin transparent'coating which is permitted to dry thereon. The de sign is then carefully eut out with a sharp knife, and the portions of the paper covering the parts which it is desired to etch or engrave are removed by loosening the edges thereof and stripping or peeling them off, any adherent particles of the coating composition being afterward removed by-scraping or otherwise detaching the same from the portions of the surface which are to be etched. The article is then placed under plied thereto a' sheet 2 of paper prepared with a coating 3 lof the described composition. It is assumed that the design to be etched on the glass consists of the letters formin vthe word Omaha, that the outlines letters have been drawn upon the surface of the paper after the attaching thereof to the glass plate 1, and that the surface of the paper has been washed over with glue-water `and dried to form a hard thin transparent 'coatingy (not indicated in the drawing). The final A of the word has been I cut out and removed,'the H has been cut out and a portion thereof is being peeled off the glass, and the other letter A is being cut out with a knife 4. It will be understood that the thickness of the parts, especially of the paper 2, is somewhat exaggerated, and

that the entire drawing is intended merely' to illustrate a typical use. of the invention..

It will be understood that the composition ',i vided by my invention is strongly adhesi ve and forms a tough, resilient and rubber-like layer or coating which oers great resistance to theaetion of a sand-blast, so

that said coating will remain adherent to and will protcctthe surface of the glass or other surface being etched, after the paper body or hacking 2 has been cut away by the sand-blast. In fact the part of the stencil which is actually effective,'in protecting the surface of the article etcl1ed,is almost solely the layer or coating formed by the coniposition, while the paper forms a mere backing or foundation which facilitates the application of thezcomposition and the formation thereof into the desired design. The cutting out of the design is facilitated by the washing over of the paper with gluewater, as described, this when dried causing the paper to be hard, stiff and relatively brittle, so that the knife may be easily pushed through it into the subjacent soft and yielding layer of the coating or composition.v The paper, by adhering more firmly to the composition than .the latter'doesl to the smooth surface of the glass or the like, facilitates the removal of the cut out parts of the design, enabling the desiredportions to be readily stripped or peeled off the surface of the article to be etched. 2

Now, having described my invention, what I claim and desireto secure by Letters Patent is:

1. A stencil-forming member, for sandblast etching, comprising a sheet of paper, a relatively thick tough pliable adhesive coating on one side of said sheet adapted to adhere to va smooth surface as of glass less 'firmly than to the paper, the `opposite side of said sheet having a design outlined thereon, anda thin coating of a transparent hard material overlying lsaid design and hardenin the .paper sheet to facilitate cut- ',ting of tie lsheet along the outlines of theA deslgn to form a stencil after the adhesive coating is applied to the object to be etched.

2. A stencil-forming member for sandblast etching, comprisin .a backing-sheet of material such as paper, aving a design outlined upon one side thereof, a dried transparent coating of sizing material overlying said design and stiiening the paper to facilitate cutting thereof upon the outlines of the design, and a relatively thick coating of `a tough pliable sand-blast-resistant material strongly adherent to the other side of said backing-sheet, said sand-blasteresistant coating adapted to adhere to a smooth surface as of glass less firmly than to the backing-sheet, whereby severed portions of the .stencil-forming membermay be readily stripped from such a surface to expose por tions thereof through the remaining parts y of said member.

oT'ro G. BEGHER, 

